Notifying response sender of malformed session initiation protocol (SIP) response messages

ABSTRACT

A method, computer program product, and computer system for notifying a response sender of a malformed SIP response message. The method includes, producing a special ACK message after receiving a malformed response message from a SIP server. The special ACK message contains a correction of the determined malformation, and is sent to the SIP server for correction by the SIP server.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of error detectionand notification, and more particularly to systems and methods fornotifying a response sender of malformed SIP response messages.

Session Initiation Protocol (“SIP”) is a peer-to-peer, application layersignaling protocol, often used in the telecommunications industry. SIPcan be used to establish, modify, and tear down IP multimedia sessionswith one or more participants. A SIP has two types of agents: a useragent client (UAC) and a user agent server (UAS). Typically, a UACinitiates a negotiation by sending a request, and the UAS sends aresponse to the request. When the negotiation is successful, the UACsends an ACK message, confirming that the UAC received the UAS responseto the request.

SUMMARY

According to an embodiment of the present invention, a method fornotification about a malformed SIP response is provided. The methodcomprises: in response to receiving a malformed response message at asession initiation protocol (SIP) client, from a SIP server, producing adedicated ACK message; sending the dedicated ACK message to the SIPserver, wherein the ACK message includes the malformed response message;and receiving, by the SIP server, the dedicated ACK message.

Another embodiment of the present invention provides a computer programproduct for notification about a malformed SIP response, based on themethod described above.

Another embodiment of the present invention provides a computer systemfor notification about a malformed SIP response, based on the methoddescribed above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a functional block diagram of a SIP environment, inaccordance with an embodiment of the present invention;

FIG. 2 depicts a flowchart illustrating operational steps of a UAC forsending a special ACK when a malformed SIP response is received from aUAS, in accordance with an embodiment of the present invention;

FIG. 3A depicts an example of a negotiation between a UAC and UAS usinga special ACK message, in accordance with an embodiment of the presentinvention;

FIG. 3B depicts an example of a negotiation between a UAC and UAS withmultiple proxy servers, in accordance with an embodiment of the presentinvention;

FIG. 4A depicts an example of a malformed response sent by a UAS, inaccordance with an embodiment of the present invention;

FIG. 4B depicts an example of a special ACK message sent by a UAC, inaccordance with an embodiment of the present invention; and

FIG. 5 depicts a block diagram of components of a computing device, inaccordance with an illustrative embodiment of the present invention.

DETAILED DESCRIPTION

Session Initiation Protocol (SIP) is a peer-to-peer, application layersignaling protocol, often used in the telco industry. SIP can be used toestablish, modify, and tear down IP multimedia sessions with one or moreparticipants. A SIP has two types of agents: a user agent client (UAC)and a user agent server (UAS). Typically, a UAC initiates a negotiationby sending a request, and the UAS sends a response to the request. Whenthe negotiation is successful, the UAC sends an ACK message, confirmingthat the UAC received the UAS response to the request. When a malformedSIP request arrives at the UAS, is responds with an error message,however, when a malformed SIP response arrives at the UAC, it does notreply with an error, thus the UAS continues to retransmit the responseuntil a timeout is reached. Embodiments of the present invention providesystems and methods for identifying a malformed response from the UASand send a special ACK message containing the exact point of error andto keep the UAS from retransmitting the malformed message.

The present invention will now be described in detail with reference tothe Figures. FIG. 1 depicts a functional block diagram illustrating aSIP environment, generally designated 100, in accordance with anembodiment of the present invention. Modifications to SIP environment100 may be made by those skilled in the art without departing from thescope of the invention as recited by the claims. In an exemplaryembodiment, SIP environment 100 includes user agent client (UAC) 120 anduser agent server (UAS) 130, interconnected by IP network 110.

In this exemplary embodiment, UAC 120 and UAS 130 are different types ofuser agents, or logical network endpoints used to manage a SIP sessionin SIP environment 100. In other embodiments, there can be multipleparticipants (multiple UAC 120 and UAS 130) in SIP environment. UAC 120and UAS 130 negotiate using SIP messages, which are text-based protocol,containing key/values, each having a start-line, header, and body, andare in the form of requests and responses. UAC 120 initiatesnegotiations by sending a SIP request and UAS 130 receives the SIPrequests and sends a SIP response to UAC 120. Often, when the responsesent by UAS 130 is malformed, there is a retransmission of the malformedresponse by UAS 130, until a timeout occurs.

IP network 110 can be, for example, a local area network (LAN), a widearea network (WAN) such as the Internet, the public switched telephonenetwork (PSTN), a mobile data network (e.g., wireless Internet providedby a third or fourth generation of mobile phone mobile communication), aprivate branch exchange (PBX), any combination thereof, or anycombination of connections and protocols that will support SIPcommunications between UAC 120 and UAS 130, in accordance with anembodiment of the present invention. IP network 110 may include wired,wireless, or fiber optic connections.

In this exemplary embodiment, IP network 110 includes proxy servers112A-N. Proxy servers 112A-N are intermediary server components for thepurpose of making requests on behalf of a client (i.e., UAC 120). Proxyservers 112A-N can make routing determinations, such as ensuring arequest is sent to an entity close to the targeted user.

FIG. 2 depicts a flowchart illustrating operational steps of UAC 120 forsending a special ACK when a malformed SIP response is received from UAS130, in accordance with an embodiment of the present invention.

In step 202, UAC 120 sends a request to UAS 130. In this exemplaryembodiment, UAC 120 sends a SIP request to UAS 130 to initiatenegotiations of an IP multimedia session, using methods known in theart.

In step 204, UAS 130 receives the request, and sends a response to UAC120. In this exemplary embodiment, UAS 130 sends a response to UAC 120,in response to receiving the request. The response sent by the UAS 130contains an indication that the message is malformed. For example, therecan be a malformation in the key/values of the header of the message.

In step 206, UAC 120 receives the response and sends a special ACK toUAS 130. In this exemplary embodiment, UAC 120 does not discard amalformed response, rather UAC 120 sends a special ACK message to UAS130, which contains the header “Error-In-Response”, in which the valueis the reason for the error. UAC 120 implements the logic to determinethe reason for the error. In some embodiments, the special ACK has theheaders of the response as a raw body, in order for UAS 130 to repairthe error (discussed further in FIG. 4B).

In step 208, UAS 130 receives the special ACK and optionally repairs theresponse and sends the repaired response to UAC 120. In this exemplaryembodiment, when UAS 130 receives the special ACK from UAC 120, whichcontains the header of the response as a raw body, UAS 130 can repairthe issue and send the repaired response back to UAC 120 to establishthe SIP session. This reduces the logic required for UAS 130 and thereliability of UAC 120, as UAC 120 can recognize the exact error in thespecial ACK, and include an exact header and body for UAS 130 to fix theidentified error.

Accordingly, by performing the operational steps of FIG. 2, thediagnostic abilities and automatic error correction (i.e., mitigationactions) can be improved in SIP environments involving many differentcomponents, as well as improving future troubleshooting and problemanalysis in SIP responses.

FIG. 3A depicts an example of a negotiation between a UAC and UAS usinga special ACK message, in accordance with an embodiment of the presentinvention.

As depicted in FIG. 3A, UAC 120 sends an initial request 302 to UAS 130.In this example, UAS 130 responds with a malformed message 304. UAC 120sends a special ACK message 306 to UAS 130, with the header as a rawbody, so that UAS 130 can repair the response. UAS 130, after making therepair, sends the repaired response 308 to UAC 120. UAC 120 then sendsan ACK response 310 to UAS 130, establishing the SIP session.

FIG. 3B depicts an example of a negotiation between UAC 120 and UAS 130with multiple proxy servers, in accordance with an embodiment of thepresent invention.

In some embodiments of the present invention, there can be many SIPentities (e.g., 100 entities or more) between UAC 120 and UAS 130, forexample, multiple proxy servers, registrar servers, etc. In the casewhere the response is malformed, the response is continually sentthrough each SIP-entity over and over again, until a timeout occurs,which may add significant network traffic to the system. As depicted inFIG. 3B, there are three proxy servers, 320A, 320B, and 320C. For eachretransmission attempt 322A-C of the malformed ‘200’ message, themessage passes through each proxy server 320A-C, reducing theperformance of each proxy server 320A-C. By using a special ACK, eachproxy server 320A-C can handle other requests and responses at the sametime, instead of putting network bandwidth toward the retransmissionattempts. This may save network traffic and allow the SIP entities(e.g., proxy servers) to achieve higher performance.

FIG. 4A depicts an example of a malformed response sent by UAS 130, inaccordance with an embodiment of the present invention.

As depicted in FIG. 4A, a malformed response 402 is sent by UAS 130(i.e., step 204). In this example, the value of the ‘Contact’ header 404is illegal, which is identified by UAC 120 as the malformation in theresponse.

FIG. 4B depicts an example of a special ACK message sent by a UAC, inaccordance with an embodiment of the present invention.

As depicted in FIG. 4B, a special ACK message 406 is created and sent byUAC 120 (i.e., step 206). UAC 120 can recognize the error in theresponse, and sends UAS 130 the reason in Error-In-Response 408. In thisexample, the body 410 of the special ACK message 406 is the originalmalformed response 402 of FIG. 4A, so that UAS 130 can repair the error.In this manner, the logic needed by UAS 130 is reduced, as UAC 120 canpoint to the exact error in the response for UAS 130 to repair.

FIG. 5 depicts a block diagram of internal and external components of acomputing device, generally designated 500, which is representative ofcomponents of FIG. 1, in accordance with an embodiment of the presentinvention. It should be appreciated that FIG. 5 provides only anillustration of one implementation and does not imply any limitationswith regard to the environments in which different embodiments may beimplemented. Many modifications to the depicted environment may be made.

Computing device 500 includes communications fabric 502, which providescommunications between computer processor(s) 504, memory 506, cache 516,persistent storage 508, communications unit 510, and input/output (I/O)interface(s) 512. Communications fabric 502 can be implemented with anyarchitecture designed for passing data and/or control informationbetween processors (such as microprocessors, communications and networkprocessors, etc.), system memory, peripheral devices, and any otherhardware components within a system. For example, communications fabric502 can be implemented with one or more buses.

Memory 506 and persistent storage 508 are computer-readable storagemedia. In this embodiment, memory 506 includes random access memory(RAM). In general, memory 506 can include any suitable volatile ornon-volatile computer readable storage media. Cache 516 is a fast memorythat enhances the performance of processors 504 by holding recentlyaccessed data, and data near recently accessed data, from memory 506.

Program instructions and data used to practice embodiments of thepresent invention may be stored in persistent storage 508 and in memory506 for execution by one or more of the respective processors 504 viacache 516. In an embodiment, persistent storage 508 includes a magnetichard disk drive. Alternatively, or in addition to a magnetic hard diskdrive, persistent storage 508 can include a solid state hard drive, asemiconductor storage device, read-only memory (ROM), erasableprogrammable read-only memory (EPROM), flash memory, or any othercomputer readable storage media that is capable of storing programinstructions or digital information.

The media used by persistent storage 508 may also be removable. Forexample, a removable hard drive may be used for persistent storage 508.Other examples include optical and magnetic disks, thumb drives, andsmart cards that are inserted into a drive for transfer onto anothercomputer readable storage medium that is also part of persistent storage508.

Communications unit 510, in these examples, provides for communicationswith other data processing systems or devices, including resources of anetwork. In these examples, communications unit 510 includes one or morenetwork interface cards. Communications unit 510 may providecommunications through the use of either or both physical and wirelesscommunications links. Program instructions and data used to practiceembodiments of the present invention may be downloaded to persistentstorage 508 through communications unit 510.

I/O interface(s) 512 allows for input and output of data with otherdevices that may be connected to computing device 500. For example, I/Ointerface 512 may provide a connection to external devices 518 such as akeyboard, keypad, a touch screen, and/or some other suitable inputdevice. External devices 518 can also include portable computer-readablestorage media such as, for example, thumb drives, portable optical ormagnetic disks, and memory cards. Software and data used to practiceembodiments of the present invention (e.g., software and data) can bestored on such portable computer-readable storage media and can beloaded onto persistent storage 508 via I/O interface(s) 512. I/Ointerface(s) 512 also connect to a display 520.

Display 520 provides a mechanism to display data to a user and may be,for example, a computer monitor, or a television screen.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

The descriptions of the various embodiments of the present inventionhave been presented for purposes of illustration, but are not intendedto be exhaustive or limited to the embodiments disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The terminology used herein was chosen to best explain the principles ofthe embodiment, the practical application or technical improvement overtechnologies found in the marketplace, or to enable others of ordinaryskill in the art to understand the embodiments disclosed herein.

What is claimed is:
 1. A computer program product for handlingnotification about a malformed SIP response comprising: a non-transitorycomputer readable storage medium; and program instructions stored on thenon-transitory computer readable storage medium, with the programinstructions including computer code for causing a processor(s) set toperform at least the following operations: in response to programinstructions to receive a malformed response message at a sessioninitiation protocol (SIP) client, from a SIP server, producing adedicated acknowledgment (ACK) message, sending the dedicated ACKmessage to the SIP server, wherein the dedicated ACK message includesthe malformed response message and a header of the malformed response ina raw body, receiving, by the SIP server, the dedicated ACK messageincluding the malformed response message, amending, by the SIP server,contents of the dedicated ACK message to correct the malformed responsemessage and thereby obtain a well-formed response message that includesall of the following: an Error-In-Response header including informationindicative of a reason for the malformation of the malformed responsemessage, and headers of the malformed response message as a raw body ofthe well-formed response message, and sending, by the SIP server, thewell-formed response message to the SIP client, to establish acommunication; wherein the sending of the dedicated ACK message to theSIP server further includes passing the dedicated ACK message through aplurality of proxy servers before arriving at the SIP server.